弹出的视图内包含UITextView，当UITextView成为第一响应者后，视图上移的位置不准确

[zhx039]

当文本框成为第一响应者后，有可能多次接收到UIKeyboardWillChangeFrameNotification通知，
在通知处理方法(keyboardWillChangeFrame:)中，设置_popupView.center的Y值是根据当前Y值计算出来的，建议通过获取键盘前后位置差值来设置_popupView.center。

// if (!CGPointEqualToPoint(CGPointZero, _markerCenter)) {
// _popupView.center = CGPointMake(_markerCenter.x, _markerCenter.y - changeHeight);
// } else {
// _popupView.center = CGPointMake(_popupView.center.x, _popupView.center.y - changeHeight);
// }

        CGRect beginKeyboardRect = [[userInfo objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue];
        CGRect endKeyboardRect = [[userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
        CGFloat yOffset = endKeyboardRect.origin.y - beginKeyboardRect.origin.y;
        _popupView.center = CGPointMake(_popupView.center.x, _popupView.center.y + yOffset - self.offsetSpacingOfKeyboard);

[Liyongcong]

没看明白

[NBTech6688]

if (!CGPointEqualToPoint(CGPointZero, _markerCenter)) {
_popupView.center = CGPointMake(_markerCenter.x, _markerCenter.y - changeHeight);
} else {
if ([self finishedCenter].y == _popupView.center.y) { //判断当前位置是否已经移动过。
_popupView.center = CGPointMake(_popupView.center.x, _popupView.center.y - changeHeight);
}
}
我这么改了下，目前还没发现问题，确实是，通知被调用了两次

[Liyongcong]

if (!CGPointEqualToPoint(CGPointZero, _markerCenter)) {
_popupView.center = CGPointMake(_markerCenter.x, _markerCenter.y - changeHeight);
} else {
if ([self finishedCenter].y == _popupView.center.y) { //判断当前位置是否已经移动过。
_popupView.center = CGPointMake(_popupView.center.x, _popupView.center.y - changeHeight);
}
}
我这么改了下，目前还没发现问题，确实是，通知被调用了两次

谢谢，试了试是可以的